It may seem like paper goods are so 20th century. But here's a link to some compelling reasons to invest in having business cards made up, and suggestions about what to put on them.
I know from my own experience that business cards are useful. When I'm online, I have difficulty knowing where to "stash" information I want to keep track of. Yes, I know there's an app for that... but then I end up with an app full of unrelated clips from here and there, and stuff gets buried pretty quickly.
A business card, on the other hand, goes right into the middle drawer of my desk, right side. But before I stash it there, I enter the info on my name-and-address spreadsheet... As this article points out, the tangible object gets handled at least once in the transition to my huge pile of "stuff I don't want to forget."
And yes, I know there are apps for scanning business cards... but it still gets handled while being scanned!